Biofouling of polymer surfaces is a ubiquitous and costly problem. Biofouling occurs when bacteria grow on surfaces known as biofilms, which secrete a thick sticky layer composed of extra-polymeric substances (EPS). 1,2 Biofouling afflicts fields as widespread as medical equipment (prosthetics, IV tubing, and dialysis membranes), commercial and private boating (hulls and propellers), and industrial and municipal liquid treatment (orange juice concentration, protein separation, desalination, and wastewater treatment). The applications most beleaguered by biofilms are membrane-based desalination and wastewater treatment processes. These processes are challenged with conditions that are ideal for the rapid proliferation of bacterial colonies and the establishment of robust biofilms on the membrane surface. The confluence of high pressures concentrating an ideal nutrient balance onto rough organic surfaces contaminated with extremely high bacterial populations represents ideal biofouling conditions.
Biofouling in membrane separation processes necessitates extensive pretreatment that incurs additional costs. Pretreatment includes chemical treatment (e.g., flocculation) and ultrafiltration (UF), which limit process efficiency and increase costs. Polyamide (PA) thin films are currently the state-of the-art material for desalination and wastewater reclamation. A solution to biofouling on PA thin films could revolutionize the entire reverse osmosis (RO) process train by reducing costs associated with pretreatment, energy for high recoveries, and capital; by reducing the plant foot print through minimized pretreatment; and by increasing membrane lifetime through reduced chemical use and biofouling suppression.